[/
 / Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
 /
 / Distributed under the Boost Software License, Version 1.0. (See accompanying
 / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 /]

[section:DynamicBuffer_v2 Dynamic buffer requirements (version 2)]

A dynamic buffer encapsulates memory storage that may be automatically resized
as required.

A dynamic buffer type `X` shall satisfy the requirements of `CopyConstructible`
(C++ Std, [copyconstructible]) types in addition to those listed below.

In the table below, `X` denotes a dynamic buffer class, `x` denotes a value of
type `X&`, `x1` denotes values of type `const X&`, `pos` and `n` denote values
of type `size_t`, and `u` denotes an identifier.

[table DynamicBuffer_v2 requirements
  [[expression] [type] [assertion/note[br]pre/post-conditions]]
  [
    [`X::const_buffers_type`]
    [type meeting [link boost_asio.reference.ConstBufferSequence ConstBufferSequence]
     requirements.]
    [This type represents the underlying memory as a sequence of @c const_buffer
     objects.]
  ]
  [
    [`X::mutable_buffers_type`]
    [type meeting [link boost_asio.reference.MutableBufferSequence MutableBufferSequence]
     requirements.]
    [This type represents the underlying memory as a sequence of @c
     mutable_buffer objects.]
  ]
  [
    [`x1.size()`]
    [`size_t`]
    [Returns the size, in bytes, of the underlying memory.]
  ]
  [
    [`x1.max_size()`]
    [`size_t`]
    [Returns the permitted maximum size of the underlying memory.]
  ]
  [
    [`x1.capacity()`]
    [`size_t`]
    [Returns the maximum size to which the underlying memory can grow without
     requiring reallocation.]
  ]
  [
    [`x1.data(pos, n)`]
    [`X::const_buffers_type`]
    [Returns a constant buffer sequence `u` that represents the underlying
     memory beginning at offset `pos`, and where `buffer_size(u) <= n`.]
  ]
  [
    [`x.data(pos, n)`]
    [`X::mutable_buffers_type`]
    [Returns a mutable buffer sequence `u` that represents the underlying
     memory beginning at offset `pos`, and where `buffer_size(u) <= n`.]
  ]
  [
    [`x.grow(n)`]
    []
    [Requires: `size() + n <= max_size()`.[br]
     [br]
     Extends the underlying memory to accommodate `n` additional bytes at the
     end. The dynamic buffer reallocates memory as required. All constant or
     mutable buffer sequences previously obtained using `data()` are
     invalidated.[br]
     [br]
     Throws: `length_error` if `size() + n > max_size()`.]
  ]
  [
    [`x.shrink(n)`]
    []
    [Removes `n` bytes from the end of the underlying memory. If `n` is greater
     than the size of the underlying memory, the entire underlying memory is
     emptied. All constant or mutable buffer sequences previously obtained
     using `data()` are invalidated.]
  ]
  [
    [`x.consume(n)`]
    []
    [Removes `n` bytes from the beginning of the underlying memory. If `n` is
     greater than the size of the underlying memory, the entire underlying memory
     is emptied. All constant or mutable buffer sequences previously obtained
     using `data()` are invalidated.]
  ]
]

[endsect]
